There is very little documentation for Leo at the moment -- particularly with respect to the code -- but the architecture and -- current resources are discussed in Leo: an Architecture for Sharing Resources for Unification-Based Grammars, a paper which will be published in the proceedings of the Language Resources and Evaluation Conference. The citation details for the paper are as follows:
Baldridge, Jason, Dowding, John, and Early, Susana, 2002. "Leo: an Architecture for Sharing Resources for Unification-Based Grammars." In Proceedings of LREC, Las Palmas, May 2002.The Java API is available here.
Source code and all supporting libraries are available in the Leo distribution release and from CVS. Anonymous checkout of the CVS is available by using the following command line instructions:
cvs -d:pserver:anonymous@cvs.leonlp.sourceforge.net:/cvsroot/leonlp login
cvs -z3 -d:pserver:anonymous@cvs.leonlp.sourceforge.net:/cvsroot/leonlp co leo
Follow the instructions in the README file in order to compile Leo. Leo comes with two example Gemini grammars in the "leo/samples" directory, and you can use the scripts provided in the "leo/bin" directory to test out the conversion and visualization utilities on these grammars.
Please post to the Leo discussion Forums if you have any questions.